(a) Field of the Invention
The present invention relates to a method for growing a silicon single crystal ingot based on a Czochralski method, and more particularly to a method of growing a silicon single crystal ingot for producing silicon wafers having uniform in-plane quality.
(b) Description of the Related Art
In general, methods for growing a silicon single crystal ingot based on a Czochralski method use a grower as shown in FIG. 1, which is a sectional view showing the inside of a general grower for silicon single crystal ingots. As shown in FIG. 1, poly-crystalline silicon is loaded into quartz crucible 10 and melted into silicon melt SM by heat irradiated from heater 30, and then silicon single crystal ingot IG is grown from a surface of silicon melt SM.
When silicon single crystal ingot IG is grown, quartz crucible 10 is ascended such that a solid-liquid interface maintains the same height while rotating an axis 20 supporting quartz crucible 10, and silicon single crystal ingot IG is pulled up while rotating it in an opposite direction to that of quartz crucible 10 with the same axis center as the rotation axis of quartz crucible 10.
In addition, to facilitate silicon single crystal ingot growth, an inert gas such as Ar gas can be generally injected into a grower and then discharged from the grower.
In such conventional silicon single crystal ingot production methods, heat shield 40 and a cooling-water jacket (not shown) for adjusting a temperature gradient of silicon single crystal ingot IG is installed. Conventional techniques using the heat shield are disclosed in Korean Patent Registration No. 374703, Korean Patent Application No. 2000-0071000, and U.S. Pat. No. 6,527,859.
However, there is a limit to production of a silicon single crystal ingot and silicon wafers having uniform quality in a radial direction when only adjusting the temperature gradient of silicon single crystal ingot IG. Therefore, there is a keen need for new techniques for producing the silicon single crystal ingot and silicon wafers having uniform quality in a radial direction.
In particular, when semiconductor devices are fabricated using silicon wafers having nonuniform quality in a radial direction, which are prepared according to the conventional techniques, the nonuniformity of quality of the silicon wafers is increased when the silicon wafers are heat-treated several times in a fabrication process of the semiconductor device. This results in a reduction of semiconductor device yield.